The present invention is directed to a gate valve which is configured to open or close an IC (Integrated Circuit) or a transfer passage which transfer processed things such as the parts of the IC from one vacuum process chamber to another vacuum process chamber, or open or close a flow passage of a fluid such as compressed fluid, gas, etc. or an exhaust gas flow passage.
Generally, in an apparatus for processing a semiconductor wafer or a liquid crystal substrate, the semiconductor wafer or the liquid crystal substrate is inserted or withdrawn from a variety of process chambers by way of a communication passageway, wherein a gate valve is typically installed in order to open or close it.
As an embodied example of the gate valve, many kinds of gate valves are disclosed. As an existing invention of such a gate valve, which is characterized in that a valve desk in a valve box is configured to freely move to a portion, and recedes from or comes into close contact with a valve seat by means of a valve rod which sealingly protrudes out of the valve box by means of an operation unit installed in the valve box. The gate valve allows the valve desk to be pressed again the valve seat in the valve box by inclined movement of the valve rod at the time the movement of the valve rod is almost finished. The operation unit may be configured to connect the piston rod and the valve rod of the piston-cylinder apparatus with the aid of the roller and the slanted long hole configured to guide the roller, or may be configured to connect their ends with the aid of a slanted link which freely pivots rotational movements.
As illustrated in FIG. 1a, the related gate valve was characterized in that the valve desk operated along a predetermined operation passageway which was slightly slanted with respect to upward and downward directions and a horizontal direction, so there was disadvantages that conflict may happen among a variety of components installed in the interior of the gate valve or that impurities produced due to mechanical abrasions could be mixed into the process chamber.
After structure of the gate valve which had a slanted, operative passageway as such was improved, as illustrated in FIG. 1b, the improved construction was proposed, in order to be able to be operated horizontally to the closing position after being operated to upper direction when it is closed.
The vacuum valve of the above said construction comprises a wall with a valve opening surrounded by a valve seat; at least one valve plate which is arranged in a vacuum region of the vacuum valve (here, the valve plate may be moved from an opening position to an intermediate position in a vertical direction, and it may be moved to from its intermediate position to a closing position in a horizontal direction which is at a right angle with respect to the vertical direction); at least one valve rod which has a valve plate (the valve rod may be guided out of the vacuum region of the vacuum valve and may move in a vertical direction or a horizontal direction wherein the vertical direction is in parallel with respect to the vertical axis of the valve rod); and a vertical drive apparatus and a horizontal drive apparatus which are arranged outside the vacuum region of the vacuum valve (the valve rod may be moved in a vertical direction or a horizontal direction by means of the above apparatuses so as to move the valve plate).
The vacuum valve of the above said construction was very efficient in its operative passageway; however, for such an operation, since it requires a vertical drive apparatus and a horizontal drive apparatus, it leaded to problems such as complicated structure, manufacturing cost. In addition, To perform accurate opening and closing operations, the vertical drive apparatus and the horizontal drive apparatus should cooperate and operate on accurate timing in set operation sequence, which leaded to a problem that more complicated components are necessary for this closely coordinated operation.